1. Field of the Invention
This invention relates to pump apparatus, and more particularly to a gerotor-type gear pump. The pump of this invention is particularly useful in applications such as transmissions, hydraulic pumps, oil pumps and the like used in the automotive and other industries.
2. Background Information
The term "Gerotor" was first used by Myron F. Hill to describe a geometry for mutually generative rotors in pumps and gears. Gerotor-type gear pumps comprise a gerotor set including an externally toothed inner gear-like rotor and an internally toothed outer rotor disposed about respective eccentric axes in an interior chamber of a housing. The rotating, meshed rotor teeth define a continuous series of expanding and contracting cavities in the chamber. The expanding cavities take fluid in from an inlet port and the contracting cavities force fluid out through an outlet port.
Although gerotor-type gear pumps are well known, existing devices and methods have significant limitations and shortcomings. Of particular importance are limitations concerning simplicity of design, flow control, and pump efficiency.
Examples of relevant apparatus and methods are disclosed in U.S. Pat. No. 2,509,321 to Topanelian, Jr. for a rotary fluid unit for take-off under variable control, in U.S. Pat. No. 4,420,292 to Lutz for bi-directional internal/external gear pump with advanced porting, and in U.S. Pat. No. 4,887,956 to Child for variable output oil pump.
Despite the need in the art for a gerotor-type gear pump which overcomes the disadvantages, shortcomings and limitations of the prior art, none insofar as is known has been developed or proposed.
Accordingly, it is an object of the present invention to provide a gerotor-type gear pump which utilizes variable axially oriented porting and variable flow control. It is a further object of this invention to provide an axially ported, variable flow gerotor-type gear pump which is automatically adjustable, highly efficient, has a simple economical design, and which overcomes the limitations and shortcomings of the prior art.